Method of making molds



G. RosENQvlsT 1,856,141

METHOD OF MAKING MOLDS March 22, 1932.

Filed Aug; 21, 192e .SMQ

INVENToR. @NW I ATTORNEYS.

Patented Mar.v 22, 1932 l UNITED* STATES:

y GUNNAR nosENQvIs'r, or PITTSBURGH-PENNSYLVANIA s METHOD or MAKING norms Application filed August 21, 19x28; f' Serial No. 301,037. v

duce a mold of a lead base alloy for use in galvanoplastic processes which possesses the characteristic of receiving-a deposition of galvanoplastic metal without causing the latter to adhere thereto and without 'requiring any preliminary preparation of the matrix surface of the mold to prevent adherence of the deposition made thereon. v

Another object of the invention is to provide a method of making molds whereby a single pattern may be utilized to form a mold having a. plurality of matrices of the shape of the article to be made. f

Molds. for forming articles of galvanoplastic metal areV generally constructed by preparing awax pattern or imprint of the surface to be reproduced, coatingthe wax member with graphite or other metallic preparation and submerging the same in an elecc tric'solution in which is provided a .cathode of scrap metal which is deposited on the coated surface of the wax member whichis constituted an anode in a suitable electrical circuit adapted vfor effecting the deposition `of metal thereon.

Molds of Vthis character are expensive to manufacture and have usually been rvmade of quent use as matrices 'for forming other articles of galvanoplastic metal. I have discovered that lead and antimony metals which were best adapted for subse-y alloys can be successfully utilized as molds timony alloys may be made into suitable mold sections by 'employing a metal spray. for effecting the depositionof the metalf either lin the form of small particles or as molten metal by'applying such powdered or molten metal to the object on which the mold section isto be formed under pressure. Y -f i Metal spraying has `been Y developed "for platingY objects and to provide a coatingon the exterior ofarticles-for various purposes.

It is applied by depositing a very thin-,layer of lcoating on the article to'be treated. In accordance with the present invention, I propose to formmolds 4of relatively heavy wall sections byfa metalspray process and by employing suche. method,` al single pattern may .be utilized to form a mold havingv any `desired-`number of matrices for reproducing a V'particular article by galvanoplastic process.

In the accompanying drawings constituting a part hereof, Vand Vin which like reference charactersfdesignate like parts, Fig. 1 -is a plan view of a patternin the form cfa-wall bracket for lighting yfixtures from-whichthe mold is to be made. Fig.`2 is a sectional elevational view of aimold made in accordance with the inventiomand Fig. 8 a sectional eleyational view 'of a.y portion of the"k mold illustrating the manner `in which it isfo'rmed. f "Referringzto Fig;3,toform a mold suchv as is illustrated in: Fig.v 2,1' place the pattern .of Fig. lonjav suitablek support" `Q'having a kplain 'smooth uppersurface 3. I then `apply acoatin'g A of metal either in powdered form ormolten metal by mean'sof the spray'y gun: 5 which operates in Lalwell known mannerfand` `which doesl not form a part yof the present "invention... `.'Iliezdeposit ca nbe made iniany desirablethickness forming lafwall section 6 which constitutesthe mold section.

After the pattern l has been completely covered with the deposited metal, it is removed and placed on the support 2 in suitable relation to the deposit formed thereon and a secondcoating isapplied which is extended over to they original deposition to form a continuous integral wall sectionand in this man nerf any desired number of matrices 7 may be formed integrally, three being shown in y ma Fig.` 3 to form a mold section which isVA 'my hand.

trimmed along the edge and assembled with other mold sections to a supporting frame 8, Fig. 2, to which it is joined to constitute a unitary mold structure capable of holding an electrolytic solution, such a mold structure having been described in my Patent No. 1,735,909.

By the use of the method described, molds can be cheaply made by the use of a single pattern and can accurately reproduce the configuration and dimensions of the pattern from which it is made. Molds as heretofore constructed were very expensive and greatly enhanced the cost of the articles-made therefrom. .With the present method, articles can be made of galvanoplastic metal, and other plastic materials, at a cost far belovsT the cost of manufacturing similar articles when made either by galvanoplastic process or by the die forming machine methods. Another advanl tage of the untilization of the present invention is in the speeding up of production, since the long delays of' Waiting on molds or dies is thereby eliminated.

It is obvious that any of the methods of forming molds as herein described may be applied to other shapes than that illustrated and for other purposes Without departing from the spirit of myinvention.

I claim herein as my invention:

`1. The method of making molds having .Y

a plurality of matrices of -identicalfform which comprises, depositing Vparticles of metal under pressure on a pattern toV form a Wall section therearound, removing said pattern andforming a deposit of metal thereon adjacentsaid first named deposit and joining the. same to'said first deposit, said deposits forming an integral mold section having matrices ofthe formV and dimensions of l the. articles to be formed.V Y

2. TheV method of making molds-Which comprises, depositing particles of metalY under pressure on afpattern to form a vWall section, removing said pattern and forming a vdeposit thereon integrally With said first named deposit, shaping said deposits to the form of'a slab to constitutesections of a `mold andV joining a plurality ofthe sections so i formed to constitute a unitary mold adaptedV to contain an electrical solution. i

In testimony whereof I haveV hereunto set l i GUNNAR nosENQvIsT. 

